A former opposition politician who has served as deputy chief of President Serzh Sarkisian’s staff for the past four years has unexpectedly resigned and said he will challenge the Armenian government in next year’s parliamentary elections.

Victor Dallakian also terminated his membership in the ruling Republican Party of Armenia (HHK), signaling plans to set up his own party ahead the elections slated for April.

Dallakian launched scathing attacks on Sarkisian as he announced his decision on Tuesday. He said the president will be responsible if “something happens” to him or his family. He did not elaborate.

“I am returning to active politics and will actively participate in the 2017 parliamentary elections,” he told a news conference.

Dallakian was one of Armenia’s most outspoken opposition lawmakers and in the early and mid-2000s, harshly criticizing then President Robert Kocharian and Defense Minister Serzh Sarkisian. In particular, he repeatedly accused Sarkisian of being a compulsive gambler.

Dallakian’s rapport with Sarkisian improved significantly after the latter succeeded Kocharian as president in 2008. In 2012, he was appointed as deputy chief of the presidential staff and Sarkisian’s legal representative to the Armenian parliament.

Speaking to RFE/RL’s Armenian service on Wednesday, Dallakian claimed that he never renounced his allegations. He also said he regrets joining the presidential administration and the HHK.

The ruling party’s parliamentary leader, Vahram Baghdasarian, scoffed at the surprise resignation, portraying Dallakian as a flip-flopper who is motivated only by his personal interests. “The Republican Party has not lost anything,” said Baghdasarian. “I have always hated ungrateful people.”

“When people see that they are forgotten, they make some claims to make their existence meaningful,” Baghdasarian told RFE/RL’s Armenian service (Azatutyun.am). “This is ridiculous.”

Some opposition leaders speculated, meanwhile, that Dallakian’s purported return to the anti-government camp was stage-managed by Sarkisian with the aim of further dividing his political opponents.

“This is definitely a pre-planned thing,” said Edmon Marukian, the leader of the opposition Bright Armenia party who defeated Dallakian during the 2012 parliamentary elections in a constituency in the northern Lori province.

“Parliamentary elections are coming up, new opposition forces have emerged and some old individuals used by the authorities are entering the fray to cause trouble and confusion,” he claimed.

Dallakian rejected such suggestions, saying that it is Marukian who has been secretly collaborating with the authorities.